Faculty Summaries
Lili Chen
Lili Chen, PhD
Associate Professor
Office Phone: 215-728-3003
Office: P0079
  • MR-Guided High-Intensity Focused Ultrasound in Cancer Therapy

    High intensity focused ultrasound (HIFU) system (InSightec ExAblate 2000) together with an MR scanner (1.5 T GE medical systems) as guidance was installed in our department (Radiation Oncology) in August 2006. HIFU has long been known to offer the potential of very precise “trackless ablation” but has only recently, with the current high quality methods of medical imaging, become a practical possibility in clinical treatment. High quality image techniques can provide precise visualization and localization of tissue damage. The potential clinical applications for cancer treatment include brain cancer, breast cancer, liver cancer, prostate cancer and bone metastases. With our current system we have treated 2 patients with bone metastases to relieve patient pain. The ultrasound can also be emitted in short, high-energy pulses resulting in focused regional shock waves that may alter vascular/cell membrane permeability without permanently damaging the tissue. The increased vascular permeability/cell membrane will concentrate macromolecular pharmaceutical agents to the treatment target and MR imaging can be used to place the ultrasound beam in the treatment target with 1 mm accuracy and monitor the effects of the treatment in near real time (with 3 second delay) using MR thermometry. In addition, MR imaging can be used for the assessment of ultrasonic treatment outcomes. Studies have been done to investigate the effects of the treatment in combination with radiation. The significance of this study is to demonstrate that the increase of anti-cancer drug uptake in prostate tumors, in combination with radiation, will have the potential to greatly improve local control in prostate cancer patients.

  • MRI-Based Treatment Planning and MRS Guided Radiotherapy

    Our previous studies were focused on MRI-Based Treatment planning for prostate IMRT, where the treatment geometry can be properly simulated using homogeneous geometry for dose calculation and treatment setup. MRI-based treatment planning for radiation therapy has been implemented clinically at FCCC. MRI-based planning can be applied to other treatment sites provided that the treatment geometry does not include significant heterogeneities, such as large air cavities or bony structures. A good candidate for such treatment is the brain. CT and MR fusion errors can be a few millimeters for brain patients due to the geometric complexity of the bony structures. Treatment planning based on MRI alone can remove this fusion error. We have investigated the dosimetric accuracy of MR-based treatment planning for brain tumors. Our current 1.5 T MR scanner not only offers us better quality of MR imaging for MR simulations compared with our previous MR unit (the 0.23 Tesla MR scanner, Philips Medical Systems, Cleveland, OH), but also allows us to perform MR spectroscopy (MRS). In addition, the MR spectroscopy (MRS) has been clinically implemented since October 2006. Prostate and brain cancer patients can be scanned routinely for the spectroscopy. The MRS can help the oncologist to determine the treatment target more precisely, resulting in better radiation treatment outcomes for patients.